Changes in cognitive function and functional brain networks in chemotherapy-exposed patients with breast cancer: A longitudinal study

Abstract

Despite the accumulating evidence on cognitive impairment in patients with cancer after chemotherapy, it remains unclear whether changes in cognitive function after chemotherapy are related to changes in brain function, because most of the previous studies were cross-sectional. Additionally, little is known regarding changes in functional brain network topological measurements (which quantify different features of brain network organization) after chemotherapy. Therefore, by applying graph theoretical analysis to resting-state functional magnetic resonance imaging data in a longitudinal study design, we investigated whether patients with breast cancer (n = 17) had changes in cognitive function and in topological properties of the functional brain network before and after chemotherapy (particularly within 6 months to 1 year after chemotherapy) and whether these changes were correlated. Patients exhibited a higher cognitive function (visual and spatial memory) and some network topological properties at a certain sparsity threshold after treatment, showing better memory function, network segregation, and small-worldness. We also observed a correlation between changes in the observed cognitive functions and network topological properties. These novel findings improve our understanding of the long-term effects of chemotherapy on cognitive function and functional brain network in patients with breast cancer, revealing part of the trajectories of changes after chemotherapy. Furthermore, these findings provide insights into cognitive and neural recovery and the associated neural mechanisms of network topological properties.